Studies of the Terrestrial Atmosphere

该项目结合了对中间层和热层氧化学的观测和实验室研究。第一个任务是阐明导致夜光中钠D2/D1线比变化很大的化学机制。虽然这是一个新发现的现象，但现在从不同地点和环境的重复测量中可以明显看出，这一比率代表了连接Na、NAO、O(3P)、O2和O3的中层化学的一个窗口。这种可变性似乎反映了钠夜辉区内[O]/[O2]比值的变化，因此代表了这一比值的探测。第二项任务是用O2和O原子作为对撞机，在v=3-8的振动范围内对O2(B)分子的损失率系数进行实验室研究。这将有助于更好地了解这些分子在大气中的产生率及其产生机制。第三项任务是调查在中间层看到的O2大气波段排放。已经观察到，各种振动能级并不一致地变化。该项目将检验发射强度比可能与中层O原子密度变化有关的假设。第四项任务试图解释氧红线发射和氮双星在520纳米处的红线发射的理论和观测之间的差异，因为它们在整个晚上都在衰减。当排放在傍晚最强烈时，观测到的强度比和模拟的强度比之间有很大的差异，红线相对于氮排放的强度比预测的更强烈。该项目将进行进一步的测量和数据评估，以了解这一差异的来源。这些研究的更广泛影响包括博士后学者的支持和对其他学科的贡献；对于后者，O2实验室研究调查较低O2电子态的较低振动水平，与O2线圈激光研究、等离子体刻蚀和气体放电系统中的非平衡过程直接相关，而钠研究将导致对流星痕迹化学的重要洞察。

This project combines observational and laboratory investigations of mesospheric and thermospheric oxygen chemistry. The first task is elucidation of the chemical mechanism that is responsible for the large variability in the sodium D2/D1 line ratio in the nightglow. Although a newly recognized phenomenon, it is now evident from repeated measurements in different locations and environments that the ratio represents a window into the mesospheric chemistry that links Na, NaO, O(3P), O2, and O3. It appears likely that the variability reflects the changing [O]/[O2] ratio within the sodium nightglow region, and thus represents a probe of this ratio. The second task involves laboratory studies of the loss rate coefficients of O2(b) molecules over the vibrational range of v = 3-8 range, using both O2 and O-atoms as colliders. This will lead to an improved understanding of the atmospheric production rates of these molecules and their production mechanisms. The third task is an investigation of the O2 Atmospheric band emissions seen in the mesosphere. It has been observed that the various vibrational levels do not vary in concert. The project will test the hypothesis that the emission intensity ratios can be related to variations in the mesospheric O-atom density. The fourth task seeks to explain a discrepancy between theory and observations for the oxygen red line emissions and those from the nitrogen doublet at 520 nm as they decay throughout the night. When the emissions are most intense in the early evening, there is a substantial difference between the observed and modeled intensity ratio, the red lines being more intense with respect to the nitrogen emissions than predicted. The project will carry out further measurements and data evaluations to understand the source of this difference. The broader impacts of these studies include the support of a postdoctoral scholar and contributions to other disciplines; for the latter, the O2 laboratory studies, which investigate the lower vibrational levels of the lower O2 electronic states, are of direct relevance to O2 COIL laser studies, to plasma etching, and to non-equilibrium processes in gas discharge system, while the sodium study will lead to important insights into the chemistry of meteor trails.